Are ultra-processed foods a public health hazard?

I'll gather the latest evidence on whether ultra-processed foods pose a public health hazard.

Yes - major health bodies and a rapidly growing body of epidemiological evidence considers diets high in ultra-processed foods (UPFs) an emerging major public health hazard, although the extent to which "ultra-processing" itself is the cause remains debated.

1. What are ultra-processed foods?

The term originates from the NOVA food classification system, which defines food in four categories, ranging from least to most processed:

•Unprocessed or minimally processed foods like fruit, vegetables, milk, or fish

•Processed culinary ingredients like salt, sugar, olive oil, and butter

•Processed foods, such as jam, pickles, or canned fruit

•Ultra-processed foods, like energy drinks, instant oatmeal, sliced bread, or hot dogs

More formally, UPFs are defined as ready-to-eat or ready-to-heat industrial preparations made largely or entirely with substances extracted from food, often chemically modified, with additives, and with a small proportion of whole food. The term includes soft drinks, packaged snacks, sugared breakfast cereals, cookies, processed meats, and packaged frozen or shelf-stable meals, but also flavored yogurts, low-calorie or low-fat products.

They undergo multiple industrial processes and often contain colours, emulsifiers, flavours, and other additives. These products also tend to be high in added sugar, fat, and/or salt, but are low in vitamins and fibre.

They make up a large share of modern diets:

•They can account for up to 58% of total daily energy intake in some high income countries

•A recent review found UPFs make a considerable contribution to national diets, ranging from 15% to 58% as a proportion of daily energy across countries

•In the U.S., they make up a majority of the calories Americans consume

2. Evidence linking UPFs to adverse health

Largest umbrella review

The largest-ever review, published Feb. 28, 2024 by The BMJ, came from a review of 45 analyses published in the last three years, involving about 10 million people in total. That number corresponds to the 32 health problems noted.

When scientists graded the evidence, they found the most convincing or highly suggestive evidence linked diets rich in ultra-processed foods with increased risks for premature death, cardiovascular disease, mental health disorders, diabetes, obesity, and sleep problems. Associations between ultra-processed foods and asthma, gastrointestinal disease, some cancers, and other health issues were limited and need further investigation.

In detail:

> Consistent evidence shows that higher exposure to ultra-processed foods is associated with an increased risk of 32 damaging health outcomes including cancer, major heart and lung conditions, mental health disorders, and early death

•Convincing evidence showed that higher ultra-processed food intake was associated with around a 50% increased risk of cardiovascular disease related death, a 48-53% higher risk of anxiety and common mental disorders, and a 12% greater risk of type 2 diabetes

•Highly suggestive evidence also indicated that higher ultra-processed food intake was associated with a 21% greater risk of death from any cause, a 40-66% increased risk of heart disease related death, obesity, type 2 diabetes, and sleep problems, and a 22% increased risk of depression

•Evidence for the associations of ultra-processed food exposure with asthma, gastrointestinal health, some cancers and cardiometabolic risk factors, such as high blood fats and low levels of 'good' cholesterol, remains limited

The findings show that diets high in ultra-processed food may be harmful to many body systems and underscore the need for urgent measures that target and aim to reduce dietary exposure.

Other prospective cohort meta-analyses

A systematic review and meta-analysis of 25 prospective cohort studies found:

> A consistently positive association between high UPF intake and increased risk of developing diabetes (37%), hypertension (32%), hypertriglyceridemia (47%), low HDL cholesterol concentration (43%), and obesity (32%) was observed

The authors noted consumption of ultra-processed foods has been shown to negatively impact human health with long-term effects on cardiometabolic health, increasing risk of obesity, type 2 diabetes, dyslipidemia, and cardiovascular disease.

Other studies:

•Those who ate the most ultra-processed foods had a 17% higher chance of developing cardiovascular disease compared with those who ate the least, with sugary drinks and processed meats the riskiest categories.

•People who eat higher amounts of ultra-processed foods - which tend to be high in sodium, sugar, and unhealthy fats - face higher risks of a host of health problems

3. Why would UPFs be hazardous? Proposed mechanisms

Researchers propose multiple pathways, but causality is not yet proven:

•Nutritional profile: high in refined grains, sodium, added sugars, saturated fat, energy density, low fiber.

•Behavioral: formulation designed to be convenient and appetising, and circumstances of consumption promote excessive food intake

•Industrial: cosmetic additives (dyes, artificial sweeteners, emulsifiers), contaminants such as phthalates, bisphenols, mineral oils and microplastics, and displacement of fresh/minimally processed foods and traditional meals

4. Debate and limitations - is it processing itself?

Despite consistent associations, the scientific community notes important caveats:

•The overwhelming majority of evidence linking UPFs to worse health is observational, where cause and effect are inferred. A widely accepted limitation is that causal inference cannot be made, as unmeasured confounding has potential to explain associations

•There is a paucity of direct causal evidence on UPFs and health or evidence of mechanism(s) from experimental studies

•There is one widely cited randomised control trial on UPFs, energy intake, and weight gain. A major limitation was that foods in the UPF condition had a different macronutrient profile to the non-UPFs and this resulted in a higher food energy density, so one cannot disentangle influence of macronutrient profile from level of processing.

•UPFs are a very wide and diverse collection of foods characterised by many different ingredients and processing techniques. Therefore, unless all types of UPF harm health, the specific mechanisms will dictate which specific UPF product types harm health

•Critics argue UPF classifications capture many unhealthy foods, but they also sweep in items that are nutritionally sound or even beneficial. Research notes substantial heterogeneity in health outcomes across UPF subtypes, with products like certain dairy products demonstrate neutral or protective effects.

•A perspective in PLOS Medicine concluded: Based on the balance of current evidence, we do not believe it is appropriate to be advising consumers to avoid all UPFs and we await further evidence to inform consumer guidance on the need to limit consumption of specifics foods based on their degree or type of processing. The authors also warn that avoiding all UPFs would cause substantial inconvenience, time, and/or economic cost, particularly for lower socioeconomic groups.

The quality of evidence was often graded as low or very low, and risk estimates varied significantly depending on methodology used to assess UPF intake.

5. Public health perspective

Public health authorities increasingly treat high UPF consumption as a hazard requiring policy action:

•The BMJ umbrella review authors conclude: "These findings support urgent mechanistic research and public health actions that seek to target and minimise ultra-processed food consumption for improved population health"

•A linked BMJ editorial argued reformulation does not eliminate harm, and profitability discourages manufacturers from switching to make nutritious foods, so public policies and action on ultra-processed foods are essential. Proposed measures include front-of-pack labels, restricting advertising and prohibiting sales in or near schools and hospitals, and fiscal measures that make unprocessed or minimally processed foods as accessible and cheaper than ultra-processed foods. Editors called for a framework convention on ultra-processed foods similar to the framework on tobacco.

Public perception aligns with this concern. A June 2025 nationally representative survey of 2,000 U.S. adults found:

•More than 60% agreed that such foods are addictive and major causes of obesity, Type 2 diabetes and heart disease

•Nearly 70% believe ultraprocessed foods are addictive

•Respondents perceived the health risks as less serious than cigarettes but roughly equivalent to alcohol and worse than fast food or cannabis

•More than 80% supported requiring government to test laboratory-made chemicals for safety before use, and roughly two-thirds supported national education campaigns, restrictions on advertising to children, banning dyes and warning labels

Bottom line

Current evidence consistently associates higher UPF exposure with higher risks of cardiovascular death, type 2 diabetes, obesity, depression, anxiety and all-cause mortality, supporting classification as a public health concern. However, because most data are observational, heterogeneous in classification via NOVA, and confounded by overall diet quality and energy density, researchers caution against labeling all ultra-processed foods as equally hazardous or advising total avoidance until mechanisms and which subtypes drive harm are clarified.

Standard public health advice remains: limit foods high in added sugar, salt, saturated fat and energy density — which heavily overlap with UPFs — and prioritize whole, minimally processed foods, while awaiting stronger mechanistic and interventional research.

Citations (5)

1pmc.ncbi.nlm.nih.govAcademic
Ultra-Processed Foods and Human Health: A Systematic Review and Meta-Analysis of Prospective Cohort Studies - PMC
Backs: “Processed foods, such as jam, pickles, or canned fruit. Ultra-processed foods, like energy drinks, instant oatmeal, sliced bread, or hot dogs. More formally, UPFs are defined as ready-to-eat or ready-to-heat industrial preparations made largely or entirely with substances extracted from food, often chemically…”
2bmjgroup.comAcademic
Consistent evidence links ultra-processed food to over 30 damaging health outcomes - BMJ Group
Backs: “They undergo multiple industrial processes and often contain colours, emulsifiers, flavours, and other additives. These products also tend to be high in added sugar, fat, and/or salt, but are low in vitamins and fibre.”
3pmc.ncbi.nlm.nih.govAcademic
Ultraprocessed food (UPF), health, and mechanistic uncertainty: What should we be advising the public to do about UPFs? - PMC
Backs: “They make up a large share of modern diets: They can account for up to 58% of total daily energy intake in some high income countries. A recent review found UPFs make a considerable contribution to national diets, ranging from 15% to 58% as a proportion of daily energy across countries”
4cornell.eduAcademic
Americans agree: Ultraprocessed foods pose major health hazard | Cornell Chronicle
Backs: “A recent review found UPFs make a considerable contribution to national diets, ranging from 15% to 58% as a proportion of daily energy across countries”
5harvard.eduAcademic
More evidence that ultra-processed foods harm health - Harvard Health
Backs: “Evidence linking UPFs to adverse health. Largest umbrella review. The largest-ever review, published Feb. 28, 2024 by The BMJ, came from a review of 45 analyses published in the last three years, involving about 10 million people in total.”